1. Field of the Invention
The present invention relates to an endoscopic therapeutic device, such as an endoscopic injector, which is introduced into a body cavity through a channel of an endoscope and injects a medicine into a tissue part in the body cavity, and to a double tube for the therapeutic device.
2. Description of the Related Art
In general, a therapeutic device is introduced into a body cavity through a channel of an endoscope, and a diseased part in the body cavity, for instance, is subjected to various medical treatments. Jpn. Pat. Appln. KOKAI Publication No. 2001-58006 (patent document 1) discloses an injector, as an example of an endoscopic therapeutic device, which injects a liquid medicine into, for instance, a diseased part in the body cavity.
The endoscopic injector is provided with an elongated insertion section which is to be inserted into the channel of the endoscope, and an operation section which is coupled to a proximal end portion of the insertion section. The insertion section includes a double tube which comprises an outer tube and an inner tube that is advancibly/retreatably inserted in the outer tube. The operation section performs an advancing/retreating operation of the inner and outer tubes. A hollow needle body is attached to a distal end portion of the inner tube.
When the endoscopic injector is used, the insertion section of the endoscopic injector is introduced into the body cavity through the channel of the endoscope. Then, the inner tube is advanced/retreated, relative to the outer tube, by the operation of the operation section. Thereby, the needle body at the distal end of the inner tube is projected from the distal end portion of the outer tube, or is retreated. At this time, by pushing the inner tube, the needle body is projected from the distal end of the outer tube, thereby puncturing a tissue part in the body cavity.
Conventionally, PTFE or nylon, which has a low surface frictional resistance, is generally used as a material of the outer tube and inner tube. The above-mentioned patent document 1 discloses the use of a fluororesin tube or a nylon tube.